Here are more resources!  * please note they could've changed *

UK Resources:

NHS Gender Identity Services: Specialized clinics for trans individuals.
Gender Identity Research and Education Society (GIRES): Support and resources.
Stonewall UK: Advocacy and support.
UK Trans Info: Comprehensive guide to trans healthcare.
Mermaids: Support for trans youth and families.
The Beaumont Society: Trans support and community.

US Resources:

The Trevor Project: 24/7 crisis hotline (1-866-488-7386).
GLAAD's Healthcare Guide: Navigating trans healthcare.
Planned Parenthood's Transgender Health Services: Affordable care.
Human Rights Campaign (HRC) Healthcare Guide: Trans-friendly providers.
Transgender Law Center: Legal support.
World Professional Association for Transgender Health (WPATH): Standards of care.

Online Resources:

Trans Youth Family Allies: Support for families.
Trans Student Educational Resources (TSER): Educational advocacy.
The Transgender Forum: Community discussion.

Helplines:

UK:

Samaritans (116 123)
Childline (0800 1111)

US:

National Suicide Prevention Lifeline (1-800-273-TALK)
Crisis Text Line (text HOME to 741741)

International:

International Lesbian, Gay, Bisexual, Trans and Intersex Association (ILGA)